CN1800062A - Sludge anhydration and burning process, and its systematic device - Google Patents

Abstract

The invention relates to a sludge drying and burning technique and its system devices, applying to the handling of active sludge in urban sewage treatment plants, its process flows through: wet sludge stock house, measuring bin, sludge mixer, sludge dryer, granular splitter, cooler, drying products storage bin, incinerator, smoke gas cleaning devices, which is characterized by: said incinerator is bubbling fluid bed incinerator with coal economizer, air heater fixed in its end part, high-heat smoke gas generated by burning is used to heat heat-conducting oil and cool air individually, and heat-conducting oil after being heated is transferred to sludge dryer through the circulating pump to dry wet-sludge. The invention is characterized by: take heat-conducting oil as heating medium, use the heat generated by burning dry sludge to heat heat-conducting oil and then dry wet-sludge to make full use of resources; the volume-reducing quantity after drying and burning could reach over 90%; the percentage of desulphurization in incinerator could reach 75% as a result of adopting two stage technology of sulfur removal, and the gross percentage of desulphurization meets national environmental legislation requirements. The invention accomplishes the resources, volume reduction, and innocence of sludge.

Description

Sludge drying and burning process and system and device thereof

One, technical field:

The present invention relates to a kind of sludge treatment technology, particularly disclose a kind of sludge drying and burning process and system and device thereof, be applicable to the processing of municipal sewage plant's active sludge.

Two, background technology:

The active sludge of general municipal sewage plant, butt mud state organic content reaches as high as 80%.Organic components complexity in the mud contains amounts of protein, amino acid, fat, VITAMIN, mineral oil, washing composition, corruption and plants matter, bacterium and meta-bolites, various nitrogenous, S-contained substances, volatility foreign odor thing, parasite and pathogenic microorganism etc.Volatility foreign odor thing is mainly materials such as organosulfur and organonitrogen.

Following 10 years be wastewater treatment in China market golden age, to build up thousands of sewage works, every day will be discharged water ratio above the hundreds of and even up to ten thousand tons of the excess sludge more than 80% by every sewage work, and the mud of these enormous amount will become a difficult problem following in need of immediate treatment.Whole nation urban wastewater treatment firm is produced about 1,800,000 tons/year of dewatered sludge (9,000,000 tons in moisture 80% mud); Estimate to produce 5,400,000 tons of dewatered sludges (2,700 ten thousand tons in moisture 80% mud) every year in the coming five years.The GB18918-2002 " municipal sewage plant's pollutant emission standard " of State Environmental Protection Administration's issue came into effect on July 1st, 2003, had increased the content of mud control criterion especially.

Along with the raising of wastewater treatment rate, sludge yield also constantly increases, and the treatment and disposal problem of mud is outstanding further.Clean water can work the mischief to the mankind and nature and is called sewage because of wherein containing organism, heavy metal, virus, bacterium etc. after using.Say it is partly these separated from contaminants to be transferred in the mud on the certain meaning of the purifying treatment of sewage.With respect to sewage, the approximate concentration of the pollutant component of mud is then much higher, shows as in practice:

(1) stink is big: numerous easy putrescible organism send various malodorous smells and influence environment in the processing of mud, transportation, storage;

(2) dangerous high: containing heavy metal, the deleterious organic synthesis things etc. such as zinc, copper, chromium, lead, cadmium of a large amount of virus, bacterium, protozoon and high density in the mud, all is a kind of potential danger to water resources and HUMAN HEALTH.

Sludge treatment will be carried out degree of depth harmless treatment to mud exactly, thoroughly solves mud to the pollution of environment and to the mankind's harm, and following several big task is arranged usually:

(1) reduces sludge volume: a) in water technology, adopt the method for biological or chemical directly to reduce the generation of mud, avoid and reduce the generation of mud; B) solid content of raising mud in sludge treating system;

(2) sludge quality is stable: remove and easily degenerate rotten organism in the mud;

(3) sewage sludge harmlessness: remove in the mud virus, bacterium, protozoon and the heavy metal etc. that human body or nature are had harm;

(4) recycling of mud: a) utilize the N, the P that are rich in the mud, K etc. to reclaim organic fertilizer, improve edaphic condition, promote plant growth; B) utilize the heat of large amount of organic storage in the mud to burn, reclaim heat energy.

Sludge treatment comprises that mud concentrates, digestion, dehydration, mummification or burn and finally abandon thing and dispose:

Processing mode	Effect	Handle the solid content of back mud	Handle the main component of back mud
				Concentrate	Make the mud preliminary hydro-extraction, dwindle sludge volume, for subsequent disposal creates conditions	3～8％	Same with primary sludge
Digestion	Reduce sludge quantity, prevent contaminate environment and improve utility value	3～8％	Same with primary sludge
				Dehydration	Reduce sludge volume	15～35％	Same with primary sludge
Dry	Reduce sludge volume, stablize sludge quality, innoxious	40～93％	A small amount of organism and inorganic ash
				Burn	Reduce sludge volume, stablize sludge quality, innoxious and some mud of heat energy recovery contains toxic substance or other reasons is difficult to utilize also burns	＞99％	Inorganic ash

Sludge ultimate disposal and require as follows:

(1) agricultural use: a) remove pathogenic agent, heavy metal etc. are avoided the side effect of life-time service to human body and soil; B) have the advantages that the phase of using is short, the shelf lives is long, should make fertilizer be easy to transportation, store, operate, improve sanitary condition; C) formulate the standard of comprehensively using, reduce detrimentally affect, eliminate user's distrust environment;

(2) landfill: a) the least possible volume; B) prevent secondary pollution;

(3) material of construction: material character is stable, toxicological harmless;

(4) throw the sea: ban use of.

The necessity of sludge anhydration burning:

The restriction of the selection of sludge treatment technique and sludge quality, ultimate sludge disposal mode, district administration's rules, economy, treatment scale, treatment technology, field condition etc. are closely bound up.

Domestic existing be that mud concentrates and dehydration technique substantially, mud through concentrate and dehydration after, generally water ratio can only be reduced to about 80%, and developed country just progressively requires the water ratio of mud to be reduced to 20%～30%.Therefore, efficient, economic sludge treatment technology comprises that dehydration, drying and incineration technology will have huge market.Concentrated, the mechanical dehydration only done at present can not reduce pollution, can not satisfy the health needs, therefore can not satisfy the requirement of sludge disposal.Carrying out drying sludge or burning is the inevitable choice of sludge treatment development.

Three, summary of the invention:

The objective of the invention is to disclose a kind of sludge drying and burning process and system and device thereof, be achieved as follows requirement after the sludge treatment:

(1) requirement of pollution removal: concentrate, dewater and can not remove pollutent, dry or burning is an effective way of thoroughly removing pollution load;

(2) requirement of local regulation: some country or place forbid not having the mud of advanced treatment to be disposed;

(3) requirement of ultimate sludge disposal: the use of the reuse of mud agricultural, mud landfill, material of construction all require mud nontoxic, satisfy hygienic requirements;

(4) requirement of economy: the mud after the advanced treatment, its volume is very little, reduces transportation, carrying cost, reduces the expense of landfill simultaneously, and can also heat energy utilization;

(5) assurance of technological development: the full-fledged investment and the working cost of having reduced of drying sludge and incineration technology, improved processing efficiency.

The present invention is achieved in that a kind of sludge drying and burning process, dewatered sludge technical process process: wet mud feed bin, weighing hopper, sludge mixer, sludge drier, granular separator, water cooler, mummification product bunker, incinerator, smoke eliminator, it is characterized in that: described incinerator adopts the bubbling fluidized bed incinerator, treated and exsiccant mud and Wingdale, quartz sand is mixed, add by the emulsion zone of screw feeder from furnace body, the incinerator afterbody is furnished with economizer, air preheater, burn the high-temperature flue gas heating thermal oil and the freezing air that are produced, the thermal oil after being heated leads to sludge drier dry wet mud by pipeline.Described drying machine adopts thermal oil as thermal medium, and described heating heat-conducting oil is the incinerator waste heat of native system.Semidrying spray column and sack cleaner combined system are adopted in described gas cleaning, whole sludge treating system also has lime white feeding mechanism, chilled(cooling) water supply (CWS) system and flying dust conveying, stocking system, and described semidrying spray principle is that sour gas mainly is SO in the incineration flue gas ₂, in the spray column of semidrying, SO ₂Contact with the lime slurry that sprays into, carry out the heat and mass reaction, the lime pulp-water is gasified by flue gas heating, and the obnoxious flavour in the flue gas then is attracted to the lime surface simultaneously, produces neutralization reaction with lime and generates solid-state salt.The filtering material of described sack cleaner adopts PTFE surface filtration material, possesses acidproof, alkaline-resisting, anti-hydrolysis, resistant to elevated temperatures characteristics, and the continuous firing temperature can reach 240 ℃, during acidic gas concentration≤1000PPM, there is not any influence in filtrate.

Sludge drying and incineration system device, comprise wet mud feed bin, weighing hopper, sludge mixer, sludge drier, granular separator, water cooler, mummification product bunker, incinerator, smoke eliminator, it is characterized in that: system and device is formed an automation control system, this robot control system(RCS) is used distributed control system control, be divided into sludge drying system in the robot control system(RCS), the thermal oil recycle system, fluidized-bed sludge incineration furnace system, flue gas purification system, wherein heat-conducting oil heating is utilized the high-temperature flue gas heating thermal oil that sludge incineration produced in the fluidized combustion furnace system in the thermal oil recycle system, and heating back thermal oil leads to the sludge drier dry wet mud in the drying sludge anhydration system.Sludge drier adopts the FTW700 type sludge drier that German An Deli thatch fluidised bed system company limited produces in the described sludge drying system.

Advantage of the present invention is:

(1) mud minimizing behind anhydration and incineration is obvious, subtracts capacity and reaches more than 90%, can save a large amount of landfill places;

(2) native system promptly except having selected for use the semidry process desulfurizer, sprays into lime owing to adopted the two-step desulfurization technology in fluidized bed incinerator in flue gas purification system, makes it remove part SO in burning process ₂, the desulfurization degree in the incinerator can reach 75%, and total desulfuration efficiency satisfies the national environmental protection laws and regulations requirement, therefore environment is not caused secondary pollution;

(3) waste heat that produces of sludge incineration is used to heat thermal oil, and the necessary energy of drying sludge, adopts thermal oil to be used for realizing the mummification of mud resource being fully used as thermal medium.

Four, description of drawings:

Accompanying drawing 1 is sludge drying of the present invention and incineration process flow block diagram;

Accompanying drawing 2 is gas cleaning processing technological flow block diagrams;

Accompanying drawing 3 is DCS system architecture synoptic diagram.

Five, embodiment:

With reference to the accompanying drawings 1, sludge drying technology is described

1, general introduction

The design of dehumidification system is to carrying out drying treatment from the mud behind the mechanical dehydration of sanitary sewage disposal factory.The mud of dehydration directly carries out drying at fluidized-bed, and need not with dried mud dewatered sludge (adding returning charge) to be carried out pre-treatment in tablets press.In fact this system that directly adds mud is exactly a sludge drier of operation automatically.

This cover technology is applicable to from the pressure filter mud that available pump extracts behind mechanical dehydration.The dried particles that produces can be made landfill disposal or further handle, for example, and as the auxiliary fuel of power station, Cement industry or incinerator.This particle is easy to shipment or the centre is left any area in.

2, drying process

2.1 wet mudflow journey

The mud of sludge treatment brand-name computer tool dehydration is delivered to mud metering storage warehouse (150m from the user ³), transport mud to fluidized-bed sludge drier and mixing screw with 5 sludge pumps from this storage warehouse.

---wherein 4 pumps are delivered to feed divider in the fluidized-bed sludge drier with dewatered sludge;

---another is then delivered to mud the mixing screw of mud/dust or directly delivers to the feed divider.

2.2 fluid bed dryer

It is the FTW700 type sludge drier that German An Deli thatch fluidised bed system company limited produces that the present invention adopts the fluidized-bed sludge drier, and this machine is made up of three parts from bottom to top basically:

---bellows, in the bottom of drying machine, be used for recycle gas is distributed to the different zones of fluidizer, a special gas distribution grid is equipped with in its bottom, is used for sending the inertia fluidizing agent.This plate has the firm advantage of design, and its pressure drop can be regulated, and this is crucial to whole drying machine that an amount of air-flow is led.

---interlude: this section is equipped with heat exchanger, forms heat exchanger set, and these heat exchangers carry out the dry and final particle of doing (under fluidized state, mud is distributed in surroundings) that forms with the heat transferred mud of thermal oil.

---suction hood, be used for making the dried particle of fluidizing to break away from recycle gas, and the recycle gas band the mud particulate and moisture evaporated is left drying machine.

Pump is thrown mud into the drying machine opening for feed by charging opening, and these mud are installed in the shredder assembly of each charging opening and smash.

In drying machine, the mud granule of generation is recycled gas fluidized and produces fierce mixing.

The characteristic of fluidization bed has guaranteed continuous consistent temperature and drying property.Owing to rely on the thermal capacity of himself in the fluidized-bed, the residence time is long and product amount is big, therefore, even some fluctuation of the quality of feed or moisture also can be guaranteed uniform drying.Take mud particulate and dust out of fluidized layer with the round-robin gas stream, like this, dustless mud granule adopts the rotation air lock to leave drying machine by normal discharging.

2.3 the mud particulate is handled

Adopt cyclonic separator that dust is separated with fluidizing agent with the mud particulate.Metering screw transfer roller and worm conveyor are transported to mixing screw to dust from grey storehouse.There, dust mixes with dewatered sludge, and sends back to fluid bed dryer again by worm conveyor.

2.4 recycle gas

The fluidizing agent of dryer system and chiller system all keeps a sealed preventing dust gas return path.

The recycle gas that plays rheomorphism with mud particulate and moisture evaporated band from fluid bed dryer.The mud particulate separates in cyclonic separator, and moisture evaporated adopts direct adverse current water spray mode to carry out condensation in a condensing heat exchanger.

Moisture evaporated itself, and other recycle gas is cooled to about 60 ℃ at the temperature levels about 85 ℃, the water that condensation then, condensation are got off leaves recycle gas, refluxes and does sewage disposal.

Containing the small globule in the gas from condenser separates in a steam separator.The refrigerative fluidizing agent is recycled to drying machine by 2 typhoon machines general is clean.Wherein 1 typhoon facility have speed-changing driving device (passing through frequency transformer), can suitably regulate the recycle gas flow.

Circulation in the fluidized bed cooler loop is handled in the same way, but does not have the whirlwind separator, because there is not the mud particulate.In addition, the cooling scrubber in the cooler gas loop comes condensed gas with the reuse water of sewage work.Loop gas after the steam separator then, is supplied to fluidized bed cooler as long as compress with a small-sized fan.Dewatered sludge by the cooling loop gas cooling to being lower than 40 ℃.

Oxygen level in the cooling loop is by an oxygen analyzer continuously measured.By the stack gas of continuous supplementation incineration system, make cooling gas keep low-oxygen environment.

2.5 technology heat supply

Dry necessary energy has two kinds of thermal mediums to select, and a kind of is steam, and another kind is a thermal oil.It is thermal medium that advanced in the world at present dry technology all adopts thermal oil, is example with this engineering below, when adopting fluid bed dryer to come sludge-drying thermal medium is done one relatively.

Sequence number	Content	Thermal oil	Steam (1.27MPa, 192 ℃)
				1	Fluidized bed area	7m 2	10.6m 2
2	The drier unit price		Increase by 30% approximately
				3	The investment of dehumidification system (comprising utility appliance such as water cooler, conveying machinery)		Increase by 23% approximately
4	The thermal medium annual running cost	In 5 years work-ing life of thermal oil, one time usage quantity is about 2t, counts 1920 yuan/year	Loss of steam and water calculates about 21600 yuan/year of annual running cost by 3%
				5	Power consumption		Increase 185kW approximately
6	Plant area	Little	Greatly

According to above-mentioned comparison, this engineering design adopts thermal oil as thermal medium.

The required net quantity of heat supply system of fluidized-bed comprises following equipment:

---the oil circulating system of forming by oil storage vessel, recycle pump, expansion slot and operating device.

---fluidized bed incinerator provides dry required heat.

---the by-pass valve of hot oiling system.

Adjust the steam capability of fluidized-bed with the thermal oil temperature levels.Fluidized-bed design steam capability is 5980kg/h, and hot oil temperature is 250/220 ℃.

Overheated for preventing thermal oil, when dehumidification system stops, should separate (unlatching bypath system) at once with the thermal oil loop with hot equipment, promptly there is not heat exhaustion in dehumidification system.

2.6 drying products

By air lock discharging drying products, have following characteristic:

Drying temperature :～85 ℃

Dry matter content :～92%

The finished product that come out from air lock are delivered directly to a fluidized bed cooler, and are cooled to maximum 40 ℃ temperature.By a rare gas element circuit system product is cooled off.The hot and humid gas that fluidized bed cooler product cooling produces and carries out recirculation by blower fan about washer internal cooling to 25 ℃.

It is 200m that dried particles is transported to a net volume in fluidized bed cooler cooling back by transfer roller (chapelet and worm conveyor) ³About the dewatered sludge feed bin in store, be transported to incinerator then or sell as product outward transport.

In addition, the container of dried particles (storage warehouse) also is connected with a rare gas element ventilation system.

The rare gas element of this rare gas element ventilation system is controlled from the excessive rare gas element of drying machine and by a detecting oxygen device.

When drying machine is driven, need about 20m approximately ³The dewatered sludge particle be stored in and start the storehouse, and deliver to fluid bed dryer by worm conveyor.

2.7 control principle

Because the characteristic of fluid bed dryer, system's control can be adopted a fairly simple control mode, and the manipulation require in drying machine loop is 4 major control loops altogether.These 4 major control loops are summarized below.

The rest part of system also has some subsidiary control loops, also describes in the lump, so that the control principle of total system is had a general impression.

2.7.1 volume controlled

By heat input (temperature and the flow of drying machine inlet deep fat) being controlled the capacity of sludge drier.According to available net heat and 85 ℃ of left and right sides fixed fluidized-bed temperatures, can reach one and compare rate of evaporation.The fluctuation of the fluctuation of inlet amount or charging moisture keeps the constant situation at inlet oil temperature, and rate of evaporation is changed, and the drying machine temperature also can change simultaneously.Under constant charging situation, the import hot oil temperature changes also can cause the drying machine temperature variation.When no matter which kind of situation temperature changed, automatic control system was regulated the feeding rate of charging pump respectively by the variable frequency regulating speed control device of every pump, thereby made the temperature of drying machine keep constant.Equally,, also can guarantee to reach all the time an optimal evaporation rate by regulating the energy supply of drying machine, and with the characteristic of mud and (or) moisture of mud is irrelevant.So control and operation way can only be just possible in direct charging system, because this system need not the granulation unit.And the granulation unit can't come regulation system simply according to the variation of moisture in the mud and characteristic.

Consider from reality, can utilize exhaust temperature as control tolerance.Because constant temp and product are evenly distributed in the fluidized-bed, thereby exhaust temperature is the fastest to the reacting condition of feed condition.This thermotonus can be used for regulating feeding rate at an easy rate, and the risk of producing substandard product can not arranged during charging moisture content changes.

85 ℃ cold operation has greatly increased the security of fluidized bed drying system, and the spontaneous ignition temperature that this temperature is significantly less than mud is 130 ℃.

2.7.2 fluidizing agent flow control

In order in sludge drier, to keep suitable fluidized state at any time, with fluidizing agent flow control to a constant optimum quantity.As a controlled variable, can adopt Venturi tube.Utilize this information, drying machine loop blower fan is by the automatic governing speed of variable-frequence governor.

2.7.3 drying machine gas return path pressure-controlling

Because non-condensable gases enters drying machine, must extract dry loop out to the excess air in drying machine loop, so that in the inner constant compression force that keeps of gas return path.

Pressure in the suction hood is as controlled variable, so that make the interior pressure maintenance negative pressure state slightly of drying machine suction hood.Pressure is opened an automatically controlled valve when rising, allow more withdrawing gas from the drying machine loop transport to chiller circuit.Close automatically controlled valve when pressure descends, have only a small amount of withdrawing gas to be transported to the cooler gas loop.

2.7.4 the removal of condensing heat exchanger heat

Must from system, remove again the heat energy that the moisture in the mud evaporates.Therefore, allow moisture evaporated condensation in condensing heat exchanger.

The water coolant that obtains from the sewage work exit is used for condensation and absorbs heat.

The controlled variable of removing heat is exactly the gas temperature in condenser downstream, remains on 60 ℃ steady temperature.

Control valve on the chilled(cooling) water supply (CWS) pipeline is as the discharge of regulating condensing heat exchanger.

2.7.5 dewatered sludge feed bin pressure-controlling

Similar with above-mentioned control principle, gas delivery also must be bled to the finished product dewatered sludge feed bin, keeps constant overvoltage condition slightly in the storage warehouse so that make.Dewatered sludge feed bin pressure inside is as controlled variable.Open the extraction valve that dust suction is handled during high pressure, and close extraction valve during low pressure.

2.7.6 fluidized-bed sludge drier product discharging

Dewatered sludge leaves fluidized-bed from three directions:

First direction---mud particulate enters grey storehouse under the effect of (cyclonic separator) deflated, mix the wet mud granule of formation and send back to fluid bed dryer with wet mud by spells.With wet mud blended purpose is to produce dustless particle, but not granulation, because fluidized-bed itself can generate particle.

Second direction---by an opening overflow of suction hood, thereby placed restrictions on the maximum height of fluidized layer.

Third direction---from following outflow, just in time on the air distribution plate, receive product by the rotation air lock.

The rotation air lock is an intermittent duty, and it is to start according to the uneven of fluidized-bed operting differential pressure and stop.

Its controlled variable is the difference of the observed pressure of bellows and fluidized-bed pressure computed in software between the two.Utilize the operating mode of this rotation air lock, fluidized-bed can clear excessive mud granule all the time, and these excessive mud granules such as discontinuous removing may accumulate on the air distribution plate.

2.7.7 the speed control of feed divider

The speed of sludge pump is the controlled variable as the feed divider.

The speed-changing driving device of feed divider, its rotating speed are to carry out stepless speed regulation by sludge pump speed.The two relation can be fixed by the incidence formula of a programming, and this incidence formula is an integral part of PLC program.In general, the minimum speed of sludge pump is exactly the corresponding minimum speed of divider, otherwise and is exactly the top speed of divider.Intermediate value between the minimum and top speed can be determined by linear relationship, and actual parameter can only be determined installing between start-up period.

2.7.8 mud particulate hybrid technique control

When mixing with wet mud from the mud particulate in grey storehouse, in order to form well-formed's wet mud granule, the speed of worm conveyor of discharging grey storehouse mud particulate is as controlled variable.Control the sludge pump mud that will wet according to the speed of worm conveyor and flow to the speed of agitator.

Above-described correct proportions will be determined that this is the parameter that can regulate at normal operation period between start-up period at device.

Sludge incinerator and heat source system

This engineering is provided with the fluidized-bed combustion boiler (dual-purpose is equipped with) of three burning sludges, when transporting outward, dewatered sludge (do not adopt burning disposal) or sludge disposal factory when just having begun to start, fluidized-bed combustion boiler can provide drying machine required heat with fire coal, and this moment, fuel was II class bituminous coal.

1, fluidized-bed sludge incineration technology

The fluidized-bed sludge incinerator mainly starts combustion chamber, smoke processing system and forced-and-induced draft fan etc. by furnace body, back-end surfaces, bed surface afterburning system, spray desuperheating device, worm conveyor, residual cake valve, fuel oil and forms.Wherein, furnace body is made of fluidized-bed emulsion zone and freeboard of fluidized bed, is furnished with heating surface at freeboard of fluidized bed.The fluidized-bed sludge incinerator adopts the Wingdale/quartz sand of certain particle size scope to make the bed material, and one time wind enters incinerator by air compartment through air distribution plate, makes the bed material in the stove be in normal fluidized state.Mud and Wingdale/quartz sand are sent in the stove by helixes feed equipment, and mud promptly expects to mix rapidly with red-hot bed after going into stove, is subjected to abundant heating, dry and perfect combustion.

Fluidized bed temperature is controlled between 850～900 ℃, and mud is particulate state in the fluidized-bed internal combustion, and its shared bed material weight ratio is very little.Mud enters the high temperature inert bed material of promptly being located fluidized state in the fluidized-bed in a large number and breaks up, and therefore, can not bond when mud burns in fluidized-bed.At compositions such as S that contains in the mud and Cl, in mud, to sneak into a certain proportion of Wingdale together to add in the stove, CaO that generates after the decomposition of limestone and above-mentioned substance reaction realize furnace sulfur fixation and solid chlorine, can significantly reduce SO ₂With the generation of HCl, and can alleviate the load of flue gas purifying equipment.

The fluidized-bed sludge incinerator mainly contains two kinds of patterns: bubbling fluidized bed and circulating fluidized bed.

2, bubbling fluidized bed incinerator

The burner hearth of bubbling fluidized bed sludge incinerator is made up of close phase incineration area and dilute phase incineration area.Fluidizing velocity generally is controlled between 0.6～2.0m/s, and the emulsion zone height generally is controlled between 0.8～1.2m, to guarantee fully contacting and stabilization fluid etc. of bed material and fluidizing medium in the required residing time in furnace of mud perfect combustion and the emulsion zone.The choosing of free board height then depends primarily on the elutriation particulate and carries the residing time in furnace of transport disengaging height TDH, flue gas and the layout of heating surface etc. secretly.

The fluidizing velocity of circulating fluidized bed generally between 3.6～6.0m/s, is about 2～10 times of bubbling bed.Under this fluidizing velocity, flue gas is carried a large amount of fine particles secretly and is flown away from burner hearth, enters gas-solid separating device.The solid particulate that separates is sent into lower furnace portion through the loopback of material device, forms the circulation of material.This operation scheme has guaranteed that solid materialss such as mud and sweetening agent have the sufficient residence time in burner hearth, be greatly improved the burn-off rate of mud and the utilization ratio of sweetening agent.

Circulating fluidized bed and bubbling fluidized bed sludge incinerator have obtained using widely in the sludge treatment industry because of its remarkable performance abroad.Through fully investigating and demonstration, at the practical situation of Shi Dongkou sewage treatment plant, the technological line of this programme determines to adopt the bubbling fluidized bed incinerator, the YGL-2200H type sludge incinerator that incinerator adopts Wuxi magnificent light boiler plant company limited to produce.Its reason is as follows:

● for being the fluidized bed incinerator of heat-transfer medium with the thermal oil, adopt circulating fluidized bed, easily make thermal oil heating surface wear, leakage, cause major accident owing to concentration of solid particles height in wind speed height, the flue gas in its stove;

● less and to the less demanding occasion of heat recuperation at mud handling capacity, because the circulating fluidized bed incinerator power consumption is bigger, cost performance is poor than the bubbling fluidized bed incinerator;

● relative circulating fluidized bed incinerator, bubbling fluidized bed incinerator structure is simpler, and less investment is easy to maintenance.

3, fluidized-bed sludge incinerator burning process

3.1 general introduction

The fluidized-bed sludge incinerator of this programme design and the technology of employing thereof satisfy following technical characteristic and condition:

● dewatered sludge and Wingdale/quartz sand are sent in the incinerator by dog-house by worm conveyor after mixing by a certain percentage.A wind provides the normal fluidisation of oxygen and assurance bed material for the burning of mud in air distribution plate is sent into stove.

● the fluidized-bed sludge incinerator can adapt to fluctuations within the specific limits such as component after the dewatered sludge mummification, moisture, calorific value preferably, and guarantees the qualified discharge of flue gas.It has the handiness of handling other waste simultaneously, as the dirts such as grid slag of sewage work's generation.

● incinerator can fully adapt to the variation of dewatered sludge water ratio, has 60～125% load variations scope on processing power.

● non-failure operation time was greater than 8000 hours/year.

● incinerator design and operation temperature is not less than 850 ℃.

● incinerator has been considered the burning characteristic of mud.

● incinerator can adapt to the long-term working conditions of operation continuously continuous 24 hours of every day.

● the close phase layer of fluidized bed incinerator adopts the furnace bottom bottom to send into air, makes sand grains and charging mix the mode of operation with the boiling shape.

3.2 fluidized-bed sludge incinerator burning process

Added by the emulsion zone of screw feeder from furnace body through processed and exsiccant mud and a certain proportion of Wingdale/quartz sand, the fixed carbon in the mud mainly concentrates on the emulsion zone burning, and the fugitive constituent major part is burnt at freeboard of fluidized bed.When the calorific value of mud hangs down, can in stove, add auxiliary fuels such as solar oil, keep the trouble-free burning of mud.The slag that produces in the combustion processes is discharged by furnace bottom through residual cake valve; The thin ash that flies away from incinerator with flue gas is then separated, is captured by the afterbody cleaning apparatus.The mud fluidized bed incinerator adopts the air stage feeding technology, and one time wind is sent in the bed by the air distribution plate of emulsion zone bottom, and the abundant burning for mud and/or auxiliary fuel when guaranteeing bed material active fluidization provides enough air; An amount of secondary air of putting english is arranged in the bottom of fluidized-bed freeboard of fluidized bed, tangentially spray in the stove, form swirling air stream at freeboard of fluidized bed, strengthened the disturbance of fluidized-bed freeboard of fluidized bed, make and mix very fully between gas and gas and gas and solid, guaranteed the abundant after-flame of freeboard of fluidized bed fugitive constituent and the further burning of flying away from the thin ash of emulsion zone.The secondary air of putting english has certain centrifugation to thin ash in the flue gas, can reduce the dust content of furnace outlet place flue gas, to alleviate the wearing and tearing of back-end surfaces and the load of reduction afterbody cleaning apparatus.Back-end surfaces is furnished with economizer, air preheater.Economizer and air preheater utilize washing away of afterbody high-temperature flue gas to reclaim part heat heating thermal oil and freezing air that sludge incineration produces.

3.3 firing system

The burning of mud is mainly carried out in burner hearth.The motion of considering bed material in the emulsion zone is very violent, for preventing the wear and leakage of heating surface, so do not arrange heating surface at emulsion zone.The heating surface of burner hearth all is arranged in the lower freeboard of fluidized bed top of cigarette speed, to reduce the wearing and tearing of heating surface, guarantees the safe operation of incinerator.Burner hearth is built by laying bricks or stones with high alumina matter wear-resistant temperature-resistant material, to guarantee the operation reliably and with long-term of incinerator.The emulsion zone section of incinerator burner hearth is a rectangle, and the freeboard of fluidized bed section is a square.The furnace wall of incinerator adopts the heavy boiler setting structure, and the inboard is a high-alumina refractory brick, and the outside is an insulating brick, can adapt to the thermal expansion requirement of incinerator and the atmosphere in the incinerator.Air distribution plate adopts the oil cooling structure, and the blast cap material is a heat-resistance stainless steel, guarantees during the blast cap design that cloth wind is even, the bed material does not pour in down a chimney.Be furnished with economizer and air preheater at back-end surfaces,, improve heat recovery rate to reduce funnel temperature.

3.4 incinerator igniting and standby firing system

The startup of fluidized bed incinerator and intensification realize by starting the combustion chamber.Solar oil is starting combustion chamber perfect combustion, and the high-temperature flue gas of generation enters in the stove through air compartment and air distribution plate, and fluidisation adds the hott bed material, reach the kindling temperature of mud when the bed material after, can drop into mud and Wingdale burns.Cross when low when the emulsion zone bed temperature, standby firing system utilizes solar oil to act as a fuel, and keeps that a temperature is not less than 800 ℃ to guarantee the stable burning of mud in the bed.Wherein, start the combustion chamber oil gun is set, standby firing system is provided with an oil gun.

3.5 incinerator limestone system

Owing to contain sulphur in the mud, mud can produce a certain amount of SO when burning ₂For guaranteeing qualified discharge, in sludge incinerator, mix a certain proportion of Wingdale, make it in burning process, remove part SO ₂In pit hole mouth sludge incinerating system, deliver to feeding system through the Wingdale of metering by worm conveyor and mix with mud, deliver to burner hearth by worm conveyor then and burn.

3.6 incinerator waste heat recovery unit---hot oil carrier boiler

The native system waste-heat recovery device is the hot oil carrier boiler.The waste heat that adopts burning sludge to produce removes to heat thermal oil.

This waste heat boiler and fluidized bed incinerator advantageously are designed to a molectron, by oil cooling cloth wind pull, stove inner coil pipe, economizer and air preheater form, boiler adopt force oil circulation.Thermal oil is squeezed into oil cooling cloth wind by circulating oil pump after filtering and is pulled → economizer → stove inner coil pipe → outlet, removes sludge-drying.Be cooled behind the deep fat heating mud and get back to the utilization of hot oiling systemic circulation.

Flue gas purification system

Flue gas purification system captures the two parts by removing of sour gas with particulate matter and forms.This process using semidrying spray woods tower and sack cleaner combined system.The semidrying depickling is to spray into a certain amount of lime white in flue gas, make it and the reaction of flue gas middle acid substance, and control moisture makes the reaction process that reaches " spraying drying ".It is dried solid-state that the depickling resultant of reaction is essentially, and waste water and mud can not occur.Sack cleaner is adopted in particulate matter capture measure in the flue gas.Before entering sack cleaner, in flue gas, spray into a certain amount of activated carbon powder again, objectionable impuritiess such as heavy metal and Dioxins then effectively capture in sack cleaner and remove in the absorption flue gas.

1, basic condition

The control criterion 1.1 factory smoke discharges pollutants ¹⁾(GB 18485-2001)

Sequence number	Project	Unit	The numerical value definition	Limit value
					1	Flue dust	mg/m 3	Measure average	80
2	Blackness of exhaustion	Lingemann blackness, level 2)	Measured value	1
					3	Carbon monoxide	mg/m 3	Little hourly value	150
4	Oxynitride	mg/m 3	Little hourly value	400
					5	Sulfurous gas	mg/m 3	Little hourly value	260
6	Hydrogenchloride	mg/m 3	Little hourly value	75
					7	Mercury	mg/m 3	Measure average	0.2
8	Cadmium	mg/m 3	Measure average	0.1
					9	Plumbous	mg/m 3	Measure average	1.6
10	Dioxins	TEQ ng/m 3	Measure average	1.0

Annotate: 1) every standard value of this table regulation all contains 11%O with under the standard state ₂The parameter value of dry flue gas convert.

2) the highest blackness time of flue gas, accumulative total is no more than 5min in any 1h.

1.2 inlet flue gas design variable

(1) exhaust gas volumn 17784Nm ³/ h

(2) flue-gas temperature

200 ℃ of spray column inlets

140 ℃ of spray column outlets

2, gas cleaning treatment process

Incineration flue gas enters smoke eliminator from heat boiler outlet, and objectionable impurities is effectively removed in the flue gas in refining plant, enters atmosphere after reaching specified standards.

Semidrying spray column and sack cleaner combined system are adopted in gas cleaning.Whole sludge treating system only disposes a cover smoke eliminator, and lime white feeding mechanism, chilled(cooling) water supply (CWS) system and flying dust are carried, stocking system.The flue gas no matter that a kind of operation scheme (burning sludge or fire coal) produces all passes through flue and enters this flue gas purification system.

2.1 semidrying spray column technology

2.1.1 semidrying spray principle

Sour gas mainly is SO in the incineration flue gas ₂In the spray column of semidrying, SO ₂With the lime slurry contact that sprays into, carry out the heat and mass reaction, lime white moisture is gasified by flue gas heating, and the obnoxious flavour in the flue gas then is attracted to the lime surface simultaneously, produces neutralization reaction with lime and generates solid-state salt, and its primitive reaction formula is as follows:

2.1.2 the selection of spray art

It is the outstanding characteristics of spraying drying (comprising that spraying absorbs) that the formation (atomizing) of material mist and material mist contact with air.For the economic production of good product, the selection of spraying gun and operation are extremely important.

The atomizing type of liquid (suspension, solution, emulsion) has four kinds, i.e. centrifugal pan atomizing, pressure nozzle atomizing, two fluids (pressurized air, liquid) atomizing and pressurization twin fluid atomization.

The characteristics of atomisation unit such as following table in the flue gas of refuse burning treatment system:

Project	Rotary atomizer	Pressure nozzle	Second fluid nozzle	The pressurization second fluid nozzle
					Atomizing type	The rotating centrifugal dish	Pressure	High-pressure air	Pressure+low-pressure air
The average droplet footpath	30～150μ	70～300μ	30～100μ	30～70μ
					Power	Greatly	Minimum	Maximum	Little
Maintenance	Difficult	Can	Can	Can
					Price	The highest	The most cheap	High (needing to be equipped with air compressor machine)	High
Wearing and tearing are to the influence of system	Not quite	Greatly	Greatly	Bigger

Slurry spraying adaptability	Be difficult for stopping up	Easily stop up	Easily stop up	Be difficult for stopping up
					Main purposes	The slurry spraying	Water cooling is used	Water cooling is used	Reinforced spraying and water cooling

2.1.3 semidrying spray technology

Make SO ₂The neutral reactor is in the rotating spraying and spray column (claiming the rotating spraying tower again), and this equipment is the round shape head tower that the high speed rotating atomizer is equipped with at the top.The flue gas that incinerator comes out enters in the tower with tangential direction, and spiral moves downward, meanwhile, the rotating disk high speed rotating of rotary sprayer produces very big centrifugal force, and lime white forms superfine droplet from the ejection of nozzle high speed, diameter≤the 100um of most of droplets forms great surface-area.Guaranteed that flue gas has the sufficiently long time to contact uniformly with the lime white solution that has atomized, and carries out sufficient neutralization reaction.Simultaneously flue gas heat passes to that moisture makes moisture evaporation in the solution, Ca (OH) ₂It is solid-state that particle is.The temperature of flue gas also descends thereupon.

Flue gas is 200 ℃ with the optimal temperature of lime white reaction in the tower, and this temperature has been taken into account the not requirement of dewfall.

If the temperature of reaction of flue gas is higher than the temperature of reaction of setting, then can in tower, sprays water coolant and regulate.

According to SO in the flue gas ₂Concentration, the straying quatity of adjusting slaked lime makes the consumption of slaked lime maintain most economical level.

2.2 lime white preparation and distribution system

In and the absorption agent of sour gas be pulverous Ca (OH) ₂, purity 〉=90% ships outside factory with closed tank truck and to deposit lime silo in, delivers to preparation vessel from the lime silo bottom by the metering screw transfer roller again and adds water, stirs into the lime white of concentration 10%.Flow to distribution trough again, with the header tank of pump delivery to the reaction tower top, enter rotary sprayer then, unnecessary lime white returns distribution trough from header tank.

2.2.1 lime silo

This project is established a lime silo to store the lime that ships outside factory.The lime silo volume is 20m3, can be for 6 days usage quantity.

2.2.2 lime white preparation vessel

Lime white is to prepare in the lime white preparation vessel, slaked lime enters preparation vessel from lime silo with the metering worm conveyor, quantitatively water inlet simultaneously, be configured to 10% concentration lime white, the agitator that be provided with automatic unlatching in the preparation vessel, stops, to reach the lime white homogeneous and to prevent precipitation, establish two level gages, a high position---report to the police, low level---stirrer quits work.

2.2.3 lime white distribution trough

The function of lime white distribution trough is to accept 10% concentration lime white in the preparation vessel, and the lime white in the preparation vessel is to flow in the distribution trough, again to the lime slurry pump feed by upflow tube.Distribution trough also has machine mixer and high and low two level gages that start or stop automatically, and a high position---stops charging, water inlet, low level---, and lime slurry pump stops, and stirrer quits work.

2.2.4 header tank

Header tank is built up in the above position of spray column, utilizes potential difference pressure to stablize lime white and enters the atomizer intake pressure and regulate flow.

2.5 dust-removal system

Since the nineties, external incinerator smoke purification system adopts half dry type spray column and sack cleaner in a large number, and has obtained good effect.

2.5.1 sack cleaner

The flue dust that burning produces, the product of sour gas neutralization reaction, the lime particle etc. of participating in reaction has formed the solid particulate in the flue gas.The equipment of removing solia particle in the flue gas is sack cleaner.Sack cleaner has very high efficiency of dust collection, can reach 99.9%, even higher, particularly can effectively capture for submicron particle.These characteristics are removed highly beneficial for the aerosol particles of heavy metal.More outstanding for the effect of removing Dioxins (dioxin) in addition.Dioxins in the incineration flue gas, by good burning control, major part can be decomposed, yet, the possibility of resynthesis is arranged under certain conditions.This project reduces and the dangerous temperature zone of having avoided the Dioxins resynthesis by the control of half dry type spray column to flue-gas temperature.The lime white molecule adsorbs micro-Dioxins particle in the flue gas simultaneously.In sack cleaner, the Dioxins that is adsorbed on the submicron particle is captured.In addition, the lime particle of not participating in combined reaction when flue gas sees through filter bag in the flue gas in addition can stick to and form muffin on the filter bag, obnoxious flavour will obtain the secondary reaction purification in the flue gas when follow-up flue gas passes filter bag, improve total purification efficiency, reduce the consumption of lime.

The design of sack cleaner and select the needs that will take into full account combustion product gases temperature, humidity and dust physicochemical property etc. for use.

The sack cleaner key equipment is the filter bag material, and various countries are devoted to the exploitation of filtrate technology after the eighties, and modern technologies are often used on sack cleaner with PTFE surface filtration material.Make it smoke gas treatment, chemical corrosion, stop up and disadvantage such as break has improvement greatly.The film type filter bag utilizes film surface, replace a dirt cake function with evenly fine aperture, the flue dust penetration coefficient is almost equal to zero, because the thin-film material surface frictional coefficient is low, hydrophobicity, temperature tolerance and anti-aging characteristic have made it excellent effect, filter material inside is difficult for causing obstruction during work, can keep the lower pressure-losses, improve filter material work-ing life, reduce working cost.The PTFE filter material was applied to municipal solid waste incinerator existing nearly ten years, and its effect not only can trap top efficiency with the micronic dust quantity discharged, and guarantees that system is reliable.

This process choice filtrate base material is to be made by polyimide, acidproof, alkaline-resisting, anti-hydrolysis that this material possesses, resistant to elevated temperatures characteristics, generally speaking, the continuous firing temperature can reach 240 ℃, usually, if the concentration of sour gas≤during 1000PPM, there is not any influence in filtrate.

Deashing adopts the high voltage pulse air blown, and rational recurrent interval and pulse width, and the good deashing property of filter bag have guaranteed that greatly the running resistance of equipment maintains a stable level, can not surpass 150mmH ₂O makes the treatment capacity of flue gas (dust-laden) remain at a stable status simultaneously, and total system remains operating in the environment of an efficient stable.

The parameter of fly-ash separator such as following table:

Sequence number	Project	Unit	Numerical value
				1	Model		DLM C 4/8/15
2	Efficiency of dust collection	％	99.9
				3	The design exhaust gas volumn	Nm 3/h	20000
4	Flue-gas temperature	℃	140
				5	Filtration area	m 2	480
6	Filter pocket material		The P84+PTFE coating
				7	The filter bag maximum operation (service) temperature	℃	250
8	Life of bag filter	Year	1.5
				9	Purge mode		The high-voltage pulse blowback
10	Pulse valve	Individual	40
				11	Dust remover resistance	Pa	＜1500

2.5.2 the by-pass flue of sack cleaner

Safety during for startup of assurance sack cleaner and operation is provided with bypath system.

When the flue gas that sludge incineration is come out may be lower than 110 ℃ at temperature raising period; maybe ought enter the sack cleaner flue-gas temperature greater than 240 ℃ (spray cooling failure and other reasons); for the protecting cloth bag dust collector is not subjected to dewfall, scaling loss; design has sack cleaner to cut out automatically, the bypath system that flue gas passes through from by-pass flue.

2.5.3 fly-ash separator insulation and electrical tracing

The flue gas moisture content that waste incineration produces is higher, and behind the spray column humidifying cooling, flue gas is carried a large amount of moisture content secretly, and fly-ash separator housing and ash bucket must be incubated in order to avoid the high temperature wet flue gas contacts on the cold wall, make CaCl in the flue dust ₂, CaCO ₃Easily moist adherent material can produce wall sticking phenomenon.In general, the wall temperature should not be lower than 100 ℃.

2.6 flying dust is carried and is stored

Flying dust is from spray column bottom ash bucket and sack cleaner bottom ash bucket, and above-mentioned two portions flying dust is transported to vertical continuous bucket elevator and delivers to grey storehouse by worm conveyor and chain conveyor output, regularly sends outside the factory with vehicle from bottom, grey storehouse and handles.

Flying dust is made of following part:

● sludge incineration produces flue dust;

● Ca (OH) ₂Reactant with the generation of sour gas neutralization reaction;

● do not participate in reaction remaining Ca (OH) ₂

● gac and other impurity.

2.6.1 flying dust is carried

Spray column cone bottom is provided with worm conveyor, and the flying dust of discharge enters worm conveyor then by two flap valves, by worm conveyor output, and converges to chain conveyor.

A worm conveyor is set under the sack cleaner, converges to chain conveyor through star-like unloading valve.

The material that chain conveyor is carried rises to the ash storage through chapelet again and deposits, and waits for outward transport.

2.6.2 flying dust outward transport

Flying dust is stored in grey storehouse.

Burn the about 1100kg/h of flying dust amount that line produces, grey storehouse can storage cycle be 2.5 days.Pneumatic push-pull valve, star-like unloading valve and humidification worm conveyor are set on the pipeline of Hui Cang bottom.The purpose of selecting the humidification worm conveyor for use is to prevent to put flying upward of ash and transportation dust, and flying dust is delivered to after by airtight vehicle loading and specified the landfill yard disposal.

2.6.3 the insulation of grey storehouse, electrical tracing reach " Arch-Breaking Device "

Because flying dust band moisture is more serious, therefore grey bulkhead temperature should be incubated, and does not paste within it to keep flying dust, and the above 1m of its ash bucket and ash bucket all adopts electrical tracing, to guarantee to replenish ash bucket dispersed heat in atmosphere.

Ash accumulates in the bucket, produce phenomenons such as knot arch, bridging, dead storehouse, limit arch sometimes, therefore consider to install the broken arch tube of strength at the ash bucket outer wall, utilize pressurized air to be stored in the small vessels, when broken arch work, the winding-up that throws open reaches by " critical velocity " of Air quality and outlet and solves sticking wall, knot arch, dead storehouse and limit arch obstacle.

3, public and supplies consumption

Name of material	Hour consumption	It consumption
			Ca(OH) 2	22.8kg	574.2kg
Electricity (power)	210kW	5040kWh
			(electrical tracing)	75kW
Tap water	1.86m 3	44.62m 3
			Pressurized air (P=5～7bar)	180m 3	The gap is used

Instrument and robot control system(RCS)

1 general introduction

Shanghai pit hole mouth wet sludge anhydration burning processing system is mainly by four most of compositions:

● the anhydration system of mud

With water ratio is that 70%～80% wet mud is sent in the sludge drying fluidizer, utilizes the heat of vaporization of thermal oil to fall moisture content, becomes water ratio and be 10% with interior dewatered sludge.

● the thermal oil recycle system

This thermal oil recycle system is sent into thermal oil and is delivered in the wet sludge anhydration fluidizer after the fluidized-bed sludge incinerator heats again, and by heat exchange, realizes the mummification effect, comprises simultaneously the cooling oil device behind the high temperature heat conductive oil overtemperature.

● fluidized-bed sludge incineration furnace system

The dewatered sludge of producing when anhydration system stores when a certain amount of, just starts incinerator, with burning the heat heating thermal oil that dewatered sludge obtains, thermal oil is delivered in the wet sludge anhydration fluidizer again, realizes the mummification effect.Finally utilize the heat dewatered sludge of mud itself.

● flue gas purification system

Because the dust content height that sludge incineration produces, directly enter belt fly-ash separator dust removing effects and be difficult to guarantee that a semi-dry desulphurization reactor is set, and not only desulfurization also can be collected a part of grit, alleviate the operating pressure of sack cleaner, and fume emission is up to state standards.

In order to guarantee safe, stable, the high-efficiency operation of factory, and alleviate labor intensity of operating personnel, factory's performance is brought into play to greatest extent, automatic control system is very important.Robot control system(RCS) is by monitoring the operation of each equipment, with each operation centralization, automatization, optimization, improving factory's serviceability and improving energy-saving effect, when guaranteeing security, the reasonable also various information of collection and treatment promptly provide best operational management information.

In the pit hole mouth wet sludge anhydration burning processing system engineering of Shanghai, automatic control system adopts distributed control system DCS, operator station by master control room carries out system's centralized supervisory control management, and by control station heat-conducting oil furnace system, fluidized-bed sludge incineration furnace system, flue gas purification system is carried out decentralised control.Because the anhydration system of wet mud partly is the design of VATECH company, and has adopted independently PLC control, therefore, this part PLC system can be carried out communication by Ethernet and DCS system, realize centralized supervisory control.

2 distributed control systems (DCS)

At Shanghai pit hole mouth wet sludge anhydration burning processing system engineering, also ripe DCS (MOX and the SIMATIC S7-400DCS) system that is used in each industrial circles such as power station, chemical industry, petrochemical industry, metallurgy, environmental protection, papermaking that selects the exploitation of Australian CIT company and Siemens for use realizes the monitoring of production process as Controlling System.

2.1DCS system

2.1.1DCS system architecture

The exploitation of DCS system has taken into full account workflow industry business administration-control incorporate demand, has merged field bus technique and open computer and network treatment technology.The structural representation of DCS system as shown in Figure 1.

From hierarchical structure, the DCS system can be divided into enterprise management level, system operation layer, key-course and four levels of on-site signal processing layer from top to bottom.

● enterprise management level

Enterprise management level is that the full factory central management network by the user constitutes.It can carry out communication by the system operation layer of network and this engineering, understands the related data of production run.

● the system operation layer

The system operation layer is made of engineer station, active station.The operations staff monitors production process data by active station, and the operation relevant device.The thermal technology personnel can utilize the engineer station that system is carried out maintenance management.

● key-course

System's key-course is made up of many field control stations.Control station is made up of central processing unit, power-supply system and the site disposal unit that is connected by fieldbus.System's key-course is mainly finished the calculating in comprehensive treating process (physical transformation, report to the police check etc.), loop of various signals and processing, the processing of logical circuit, the execution of advanced control algorithm etc.

● the on-site signal processing layer

It all is by realizing with the on-site processing module of fieldbus (Profibus-DP) connection that all I/O of DCS system handle.Each processing module both can be installed in the rack with central processing unit, power supply etc., also can disperse to be installed in the on-the-spot signal locker.

2.1.2DCS system hardware

2.1.2.1 grid

The backbone network of DCS system abbreviates grid as, constitutes by the Fast Ethernet network, but redundant configuration.Be used to connect field control station, engineer station, operator station, senior computer installation etc. are finished the communication and the data exchange at each station.

The characteristic of DCS grid is as follows:

Transfer rate 100Mbps

Communication media adopts twisted-pair feeder.

2.1.2.2 engineer station

The DCS system engineer is made up of top-grade computer and configuration instrument software at the station, mainly finish the configuration of database, figure, control algolithm, form and simplify the printing of parameter configuration configuration such as history library, emergency review, set of variables definition and configuration data, dress down, and finish that on-line operation monitors and functions such as management.

Configuration instrument is omnibearing Chinese software, operates under the operating system of Chinese Windows NT4.0workstation or above version.For the user provides flexible, convenient, a comprehensive engineering platform, to realize user's various control strategies.

2.1.2.3 operator station

The DCS system operator station adopts open architecture, form by equipment such as highly reliable industrial microcomputer and special-purpose industrial keyboard, trace ball and softwares such as man-machine dialogue, picture demonstration, main complete operation of operator station and function for monitoring, comprise keyboard, the mouse message of reception from the operator, the demonstration of carrying out picture is switched, or input operator's order and parameter, revises the operating parameter of system, realization is to the manual intervention of system, as on-line parameter modification, regulating and controlling etc.

2.1.2.4 field control station

Field control station be the DCS system directly with on-the-spotly come into contacts with, large-scale I/O treatment system, be one have that signals collecting, loop are regulated, logic is chain, the field control equipment of sequential control and local operation function.

Field control station partly is made up of analog-and digital-I/O module, communication module, power module and the rack etc. of main control unit, adaptation broad variety signal, solidifies real-time control software and I/O plate software on main control unit and I/O module respectively.Main control unit links to each other with grid, but redundant configuration.

Field control station has adopted distributed frame.The various processing units of field control station couple together by the control network, constitute a field control station.Promptly from logic, field control station is made up of main control unit, process input-output unit, power subsystem and control network.

2.1.3DCS system software

2.1.3.1 configuration software

DCS system configuration software package runs on the engineer station, and operating system is Chinese Windows NT4.0, and the database support programs are the SQLAnywhere of Sybase company.Mainly comprise five instruments:

● the device configuration instrument

Being used for defining the equipment configuring condition at each station of certain engineering, comprising system and device table and field control station equipment list two portions, is the configuration instrument that provides with graphics mode.

● database configuration instrument

The editor of database configuration mainly finishes the function of two aspects, and the one, the structure of all kinds of points of definition composition customer data base and the information of actual point, the one, the structure of definition control table and actual control table information.Also finish the compiling and the following dress function of system in addition.

● control scheme configuration instrument

Support that the user utilizes programming languages such as structured text (ST), FBD (FBD), ladder diagram (LD), sequential flowchart (SFC), calculation formula, generate control scheme page or leaf, can satisfy the Control Configuration demand in process control field all sidedly.

● the graphic configuration instrument

The graphic configuration tool software is with generating application system required various total looks figure, schema and working condition chart, and it is the basic comprising unit with the vector graphics object.Software provides multiple static tool formation object, and each object of drafting all has tens of kinds of kinetic characteristics, also has interaction characteristic simultaneously, is equivalent to object and has certain capacity, as pop-up window, changes data dot values etc.

● the form configuration instrument

The print format that is used for the design data form.

That the configuration software of DCS system has is flexible, easy to operate, friendly interface, characteristics such as safe and reliable, and the development along with Internet technology, object-oriented programming, software engineering, operating system simultaneously improves a lot again.Engineer station's configuration software operates under the Chinese WindowsNT4.0 environment, the user by simple CAD formula draw, fill in a form, operation such as text input, can finish using the configuration work of system.The configuration software of DCS system is full Chinese interface, meets the custom of China more.

2.1.3.2 real-time monitoring software

The real-time monitoring software bag of DCS system is become by five groups of subsystems, is distributed on each station of whole real time execution system.Mainly comprise:

● dedicated operations person's station software

Operate in the operator station, operating system is Chinese Windows NT4.0workstation or above version.Operator station mainly finishes the demonstration and the inquiry of various monitor messages, show and printing as process flow sheet demonstration, warning supervision, log query, various form and tabulation, perhaps input operator's order and parameter, the operating parameter of modification system, realization is to the manual intervention of system, as on-line parameter modification, regulating and controlling etc.

● the field control station real-time control software

Operate on the field control station, operating system is the QNX real-time system.Field control station is finished data gathering, engineering unit conversion, control computing, control output by field-bus interface; By grid data and diagnostic result are sent to system server.

● the print service system

Operate on the senior computer installation, operating system is Chinese Windows NT4.0.

2.1.3.3 schema shows and operation

The schema that the DCS system provides can be divided into several types by purposes:

● simulated technological process figure, the working condition chart of the on-the-spot main technique flow process of performance promptly defined by the user;

● system state and supervisory frame, i.e. some and the state demonstration fixed image relevant that provide by system with system management operation;

● trend display frame;

● control scheme debugging pictures.

Keyboard special, screen soft keyboard are generally used in the operation of schema, and mouse etc. are realized all operations.When operator station inserts a plurality of CRT screen, determine current session function screen by the CRT switch key or the soft key on the screen of keyboard.

Claims (9)

1. sludge drying and burning process, dewatered sludge technical process process: wet mud feed bin, weighing hopper, sludge mixer, sludge drier, granular separator, water cooler, mummification product bunker, incinerator, smoke eliminator, it is characterized in that: described incinerator adopts the bubbling fluidized bed incinerator, treated and exsiccant mud and Wingdale, quartz sand is mixed, add by the emulsion zone of screw feeder from furnace body, the incinerator afterbody is furnished with economizer, air preheater, burn the high-temperature flue gas that is produced and be used for heating thermal oil and freezing air respectively, the thermal oil after being heated is delivered to sludge drier by recycle pump and is used for dry wet mud.

2. sludge drying according to claim 1 and burning process is characterized in that: described drying machine adopts thermal oil as thermal medium, and described heating heat-conducting oil is the incinerator waste heat of native system.

3. sludge drying according to claim 1 and 2 and burning process, it is characterized in that: semidrying spray column and sack cleaner combined system are adopted in described gas cleaning, whole sludge treating system also has lime white feeding mechanism, chilled(cooling) water supply (CWS) system and flying dust conveying, stocking system, and described semidrying spray principle is that sour gas mainly is SO in the incineration flue gas ₂, in the spray column of semidrying, SO ₂Contact with the lime slurry that sprays into, carry out the heat and mass reaction, the lime pulp-water is gasified by flue gas heating, and the obnoxious flavour in the flue gas then is attracted to the lime surface simultaneously, produces neutralization reaction with lime and generates solid-state salt.

4. sludge drying according to claim 3 and burning process, it is characterized in that: the filtering material of described sack cleaner adopts PTFE surface filtration material, possess acidproof, alkaline-resisting, anti-hydrolysis, resistant to elevated temperatures characteristics, the continuous firing temperature can reach 240 ℃, during acidic gas concentration≤1000PPM, there is not any influence in filtrate.

5. sludge drying and incineration system device by any process application in the claim 1～4, comprise wet mud feed bin, weighing hopper, sludge mixer, sludge drier, granular separator, water cooler, mummification product bunker, incinerator, smoke eliminator, it is characterized in that: system and device is formed an automation control system, this robot control system(RCS) is used distributed control system control, be divided into sludge drying system in the robot control system(RCS), the thermal oil recycle system, fluidized-bed sludge incineration furnace system, flue gas purification system, wherein heat-conducting oil heating is utilized sludge incineration high-temperature flue gas heating thermal oil in the fluidized combustion furnace system in the thermal oil recycle system, and heating back thermal oil leads to the sludge drier dry wet mud in the drying sludge anhydration system.

6. sludge drying according to claim 5 and incineration system device is characterized in that; Sludge drier adopts the FTW700 type sludge drier that German An Deli thatch fluidised bed system company limited produces in the described sludge drying system.

7. sludge drying according to claim 5 and incineration system device is characterized in that: the YGL-2200H type sludge incinerator that described incinerator adopts Wuxi China light boiler plant company limited to produce.

8. according to claim 5 or 6 or 7 described sludge drying and incineration system devices, it is characterized in that: a semi-dry desulphurization reactor is set in the described flue gas purification system.

9. sludge drying according to claim 5 and incineration system device is characterized in that: the distributed control system of described automatic control adopts the DCS Controlling System of Australian CIT MOX of company and Siemens SIMATIC S7-400.

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